1. Field of the Invention
The present invention relates to a display device and a method of driving the same. More particularly, the present invention relates to a display device having a touch screen panel and a method of driving the same.
2. Discussion of the Background
In general, a plurality of pixels are arranged in a matrix form in a display device, and the display device displays an image by controlling the light strength of each pixel according to given luminance information.
A touch screen panel is a device that allows a machine, such as a computer, to perform a desired command when a finger or a touch pen (or a stylus) writes a character, draws a picture, or touches an icon on a screen. A display device to which a touch screen panel is attached determines when a user's finger or a touch pen, etc. touches the screen and determines the touch position information thereof.
A plurality of sensing units may be arranged in an approximate matrix form on the touch screen panel, and each sensing unit allows the display device to determine when a user's finger, etc. touches the screen and the touch position by detecting the change in capacitance that is generated as the user's finger, etc. touches the touch screen panel.
The sensing unit may include a variable capacitor having a capacitance that changes according to a touch and a reference capacitor that is connected in parallel to the variable capacitor. As the capacitance of the variable capacitor changes according to a touch, a junction point voltage between the reference capacitor and the variable capacitor changes according to the magnitude of the capacitance change, so that the display device may determine when there is a touch by sensing a voltage.
However, in order to form the reference capacitor, which is connected to the variable capacitor, even if the reference capacitor and the variable capacitor share one electrode, another electrode is further required. This additional electrode may complicate a process of forming the touch screen panel and may increase the thickness of the touch screen panel.